Sorry, maybe a dumb question, will you guys please explain the difference in use to me? There are some threads about the need for degreeing cams to get more horsepower, fine emissions and to compensate wear. I understand that. On the other hand I know that 360's have adjustable cams, so their cam timing moves around. Why bother to adjust to one degree knowing that offset might be better in certain conditions? Thanks.
the 360 varitor allows the cam timing to change dynamically with the engine running. Before that can work, you still have to install all the cams in the correct starting out positions. That is done by static cam timing with the engine not running.
Thanks Mitchell. I am a little confused here because 360 and others have their cams advanced for maximum engine performance. The basics should be right on the mark. So, if a fixed (3*8) cam should be accidentally advanced it might be good for performance? In case a belt should slip a tooth, the cam gets retarded. Not ideal. I believe there is no mechanical cam retarding by the 360 variators. Please correct me if I'm wrong.
The Variators move the cam timing in a very precise manner. At low RPMs, the cams are moved for more overlap, enhancing the bottom end, and bringing the engine on song earlier in the RPM band. Here, one is playing with very close tolerances between the valves and the piston tops versus the ramp rates on the cams themselves. The ramp rates themselves have about 1/2 though per degree rotation, so you get cam timing off by more than a smidgen and you have valve-to-piston "issues". Thus the variators are limited in their movements by how closely the cam timing can be set. After about 4000 RPMs, the variators bring the cams back to the low-overlap, later intake close, earlier exhaust open which gains a few ponies at the top end.
360 has huge valve piston clearance. Not an issue. Cam advances much earlier than that. just over 2000 rpm. Variation is primarily an emission issue.
Cam timing is degreed to get the motor to run as designed. With a single cam slight deviations make a far smaller difference than helter skelter timing of multi cam motors. The more highly tuned a motor is the more slight differences can matter and above all else Ferrari timing marks are not very accurate so accurate setting require different methods.
